Question: Simplify the following expression: $x = \dfrac{7}{8r} + \dfrac{1}{2r}$
Solution: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $8r$ and $2r$ $\lcm(8r, 2r) = 8r$ $ x = \dfrac{1}{1} \cdot \dfrac{7}{8r} + \dfrac{4}{4} \cdot \dfrac{1}{2r} $ $x = \dfrac{7}{8r} + \dfrac{4}{8r}$ $x = \dfrac{7 +4}{8r}$ $x = \dfrac{11}{8r}$